Certain kinds of vehicles, such as pickup trucks, are adapted to be fitted with or coupled to a unit provided with living accommodations. The arrangement is such that the truck may be used either in conjunction with or independently of the living accommodations unit. Typical of such vehicles and units are those disclosed in Prater U.S. Pat. No. 3,684,048; Miller et al U.S. Pat. No. 3,719,244; and Ward U.S. Pat. No. 3,817,545. According to the invention, a production vehicle, such as a van, is convertible from van configuration to one fitted with a living accommodations unit, and vice versa, thereby enabling the vehicle to be used in either mode.